Synthesis, photophysical, computational characterizations, electrochemical and photovoltaic characteristics of some new quinoline-based hybrid fluorescent dyes

In this work, we have designed and synthesized some new fluorescent heterocyclic systems based on quinoline unit with the aim of providing new and highly effective synthetic dyes for the development of more effective photosensitive materials. The reaction of 8-(4-chlorophenyl)-3-alkyl-5-nitro-3H-imidazo[4 ',5':3,4]benzo[1,2-c] isoxazoles with heteroaryl acetonitriles in KOH/MeOH led to the formation of novel 6H-furo[3,2-b]imidazo[4,5-f]isoxazolo[4,3-h]quinoline, 6H-imidazo[4,5-f]isoxazolo[4,3-h]thieno[3,2-b]quinoline and imidazo[4,5-f]isoxazolo[4,3-h]pyrrolo[3,2-b]quinoline at rt. The experimental results of the elemental analysis and spectroscopic data proved the proposed structures of the new fluorescent heterocyclic dyes. The optical properties of the title compounds such as wavelengths of maximum absorbance, fluorescence excitation, fluorescence emission, fluo-rescence quantum yields, and extinction coefficients were also obtained. The electrochemical characteristics of the title dyes were investigated using the cyclic voltammetry technique and reversible oxidation waves were observed at half-wave potential for these compounds. The HOMO and LUMO energy levels of the dyes were also determined by electrochemical, optical measurements and theoretical calculation. Additionally, I-V curves and the IPCE spectra of the title dyes were screened to investigate their photovoltaic performance parameters. Our experimental results discovered that the photovoltaic performances of the title dyes are in the range of 3.17-4.27 %. Electrochemical impedance spectroscopy (EIS) analysis was also performed to further elucidate the photo-voltaic properties of the dyes.